Floor treating machines have been used for many years to polish floors and/or clean carpets. Such machines typically include a top-hat-like hollow housing with an elongated handle angled upwardly toward a user. Attached to the housing is a motor having a rotatable drive shaft that extends through the housing and is connected to a circular brush ring. The brush ring may include cleaning bristles, coarse or smooth pads, or any other surface for cleaning or polishing depending on the type of floor to be cleaned or polished.
In these prior art machines, the motor drive shaft is coaxially connected to the brush ring. When the motor rotates the drive shaft, the coaxial connection causes the brush ring to rotate identically with the shaft. While this rotational motion adequately polishes floors, a back-and-forth scrubbing motion is more effective for cleaning. When using the prior art machines, the user must manually move the entire machine back and forth to create the desired scrubbing motion. Such manual motion takes much effort and still inadequately cleans because of the inability of a user to manually move the machine back and forth fast enough to thoroughly clean the floor.
To overcome some of the disadvantages of these prior art machines, the assignee of the present invention previously developed and sold a small ten-inch diameter floor machine that provides an orbital motion to its brush ring. In that machine, the motor was mounted directly on the machine housing with a drive shaft extending through the housing. A bearing assembly was eccentrically mounted on the drive shaft such that the bearing assembly rotated and moved orbitally about the motor shaft. A brush ring carrier was attached to the bearing assembly by screws to translate the rotational and orbital motion to the brush ring. A series of small, flat washers, each having a radial side more heavily weighted that its opposite side, were placed between the bearing assembly and the motor to counterbalance the orbital motion of the brush ring caused by the eccentric mounting of the bearing assembly.
The design of the previous orbiter floor machine sold by the assignee of the present invention worked adequately for a small 10-inch machine, but the design could not be used for larger machines such as the 17-, 20-, and 24-inch machines commonly available (size refers to the diameter of the brush ring used). In such larger machines, the small washers of the small machine could not sufficiently counterbalance the force caused by the orbital motion. Such washers have a substantial portion of their weight centrally located such that the weight of the washers needed to counterbalance the increased radius of the brush tings of the larger machines is much greater that would be the case for a counterbalance weight located further from the shaft. If more washers are added to provide the necessary counterbalancing weight, the counterbalancing forces will act on a plane at a substantial distance from the forces at the brush ring that are intended to be counterbalance. As a result, the system becomes out-of-balance and unstable with vibrations being transmitted to the user.